Call waiting features for telephone service are well-known in the art. Call waiting enables a party busy on another call to learn about an incoming call and gives the called party the opportunity to interrupt the ongoing call to accept the incoming call. Currently available call waiting features signal the called party with a single, predetermined tone to indicate that a call is waiting. While call waiting is a useful feature which enables a called party to discontinue lesser important telephone calls in favor of emergency or important calls, subscribers to a call waiting service may be annoyed by unwanted calls. Subscribers may feel that call waiting interferes with the called party's privacy and that important calls are interrupted by unwanted calls. The called party may feel obligated to accept a waiting call on the possibility that the waiting call is important.
Various forms of call waiting have been suggested to alleviate the problem of responding to calls for fear that an important call will be missed. In particular, various forms of caller identification techniques have been combined with call waiting to give the called party an indication of the caller's identity. Having the caller's identity, the called party is in a position to decide whether to interrupt an ongoing telephone call in favor of answering the incoming call. However, these caller identification techniques often require special telephone equipment, such as an Integrated Services Digital Networks (ISDN) phone or a special database for assigning a caller's identity on the basis of the caller's automatic number identifier (ANI).